Extractor-switch mechanism for machine guns



July 16, 1946. c. G. SWEBILIUS 2,404,325

EXTRACTQR-SWITCH MECHANISM FOR MACHINE GUNS Filed Nov. 19, 194:5 g Sheets-Sheet 2 hue/7 fa y (81 6. J'WeAi/r'u;

Patented July 16, 1946 EXTRACTOR-SWITCHMECHANISM Fen YMACHJNE GUNS Carl G. Swebilius, Hamden, Conn, assignor to The High Standard Ma Hamden,

nufacturing Company, Conn., a. corporation of Connecticut Application November 19, 1943, Serial No. 510,854

2 Claims.

The present invention relates to improvements in machine guns and relates more particularly to improvements in extractor-switch mechanisms therefor. The extractor-switch mechanism of the present invention is adapted for use in connection with machine guns of the so-called Browning type, which type of machine gun is disclosed in detail in United States Patent No. 1,628,226, dated May 10, 1927.

In machine guns of the Browning type above referred to, a pivotal cartridge-extractor is employed which serves to extract a, fresh cartridge from a belt of cartridges as the breech-bolt moves rearwardly. Such cartridge-extractor is so actuated that upon the rearward stroke of the breechbolt, a given cartridge from the belt is carried rearwardly and depressed by the said cartridgeextractor and ultimately brought into alignment with the cartridge-chamber of the barrel during the forward travel of the said breech-bolt. The latter part of the cartridge-depressing action of the cartridge-extractor just referred to is accomplished by a pivotal extractor-switch which serves to further depress the forward end of the cartridge-extractor as the breech-bolt moves forwardly. Shortly before the breech-bolt reaches its breech-closing position, the forward portion of the ex-tractor-switch is depressed so that the said extractor-switch then serves to guard against the subsequent depression of the cartridge-extractor until such time as the breech-bolt is again moved rearwardly. As will more fully hereinafter appear, the present invention relates to improvements in features directly related tosuch an extractor-switch.

One of the objects of the present invention-is to provide a superior extractor-switch mechanism for machine guns characterized by simplicity and ability to withstand hard usage over long periods of service.

Another object of the present invention is to provide a superior extractor-switch mechanism capable of satisfactorily functioning in a machine gun when the latter is operated at speeds in excess of one thousand shots per minute.

With the above and other objects in view, as will appear to those skilled in the art from the present disclosure, this invention includes all features in the said disclosure which are novel over the prior art and which are not claimed in any separate application.

In the accompanying drawings, in which certain modes of carrying out the present invention are shown for illustrative purposesr Fig 1 is a broken View partly in side elevation and partly in vertical longitudinal section of the rear portion of a machine un equipped with an extractor-switch mechanism embodying the present, invention, the parts being shown in the positions which they assume when the breech-bolt has almost reached its rearmost position and the barrel-extension has reached the limit of its rearward travel;

Fig. 2 is a View similar to Fig. 1 but showing the parts in the positions which they assume when the barrel-extension has reached its .full forward position and the breech-bolt is approaching-itsfull breech-closing position;

Fig. 3 is a broken view of a portion of therleft side-plate of the machine gun looking toward the louter face thereof;

Fig. 4 is a view similar to Fig. 3 but looking toward the inner face of the side-plate;

Fig. 5 is a transverse sectional View taken on the line 5'5-of Fig. 4; n

Fig. 6 is a similar view taken on the line 6-6 of Fig. 4;

Fig. 7 is a view in side elevation of the extractor-switch spring detached;

Fig. 8 is an edgeview thereof; and

Fig. 9 is a perspective view of the extractorswitch detached.

The machine gun illustrated in the accompany ingdrawings is of the Browning type and includes a receiver generally designated by the ref erence character 'I 9, an axially-reciprocatin barrel H, a barrel-extension l2, a breech-bolt l3 and abarrel-jacket l4.

The rear end of the barrel 1 I is extended within the forward end of the receiver I0 for reciprocation therein, and the forward end of the aforesaid barrel-extension I2 is rigidly organized with the rear end of the said barrel for reciprocation also within the receiver III, in a, manner well known in the art. Both the breech-bolt I3 and the barrel-extension l2 (and hence also the barrel H) may be respectively urged forwardly by suitable spring-means, not herein shown but well understood in the art and more fully shown in the Browning patent before referred to.

The breech-bolt l3 reciprocates both with and with respect to the barrel-extension l2 in a mannerwell known in the art. The said breech-bolt I3, is carried by the barrel-extension 12 but with capacity for reciprocation with respect thereto, as before referred to.

Pivotally connected at its rearend to the left side of the breech-bolt I3 is acartridge-extractor. generally designated by thereference character l5. At its forward end, the cartridge-extractor I is formed with a depending cartridge-extracting hook I6 which is adapted in a manner well known in the art to successively hook into the respective cannelures of cartridges to effect the successive individual extractions thereof from a, cartridge-belt such as I1 indicated in Figs. 1 and 2.

Extending laterally outwardly from the forward end of the cartridge-extractor I5 i an integral guide-lug I8 which is adapted to coact with the edge surfaces of a lever-like extractorswitch generally designated by the reference character I9. all as will more fully hereinafter appear.

Rigidly carried by the under-face of the topplate of the receiver II) is a downwardly-andrearwardly sloping extractor-depressing cam 2| positioned so as to engage with the upper surface of the forward portion of the cartridge-extractor I6 to depress the same when the breech-bolt I3 moves rearwardly, as indicated in Fig. 1.

About midway of its length, the extractorswitch I 9 above referred to is formed with an integral outwardly-extending and cylindricallycontoured pivot-stud or trunnion 22 which turns in a bearing-opening 23 extending laterally through the left side-plate 24 of the receiver I6. The said pivot-stud 22 is of a length materially exceeding the thickness of the side-plate 24, so as to extend outwardly well beyond the outer face of the said side-plate. Adjacent its rear end, the extractor-switch I8 is formed with an outwardly-projecting limiting-lug 25 fitting into a recess 26 formed in the inner face of the sideplate 24 before referred to. By its engagement with the upper wall of the recess 26, the said limiting-lug 25 serves to limit the upward swinging movement of the rear portion of the said extractor-switch I9.

At a point slightly outwardly with respect to the outer face of the side-plate 24, the pivot-stud 22 of the extractor-switch I9 is formed with a diametric passage or socket 21. Extending downwardly through the passage 21 just referred to is the key-portion or tension-finger 2B of an extractor-switch spring generally designated by the reference character 29. The said spring 29 may be conveniently formed of relatively-heavy spring-steel wire and includes also a loop-portion 30 and a relatively-long tension-arm 3I.

In the normal unrestrained condition of the extractor-switch spring 29 above referred to, the key-portion 28 thereof is displaced outwardly with respect to the outer face of the side-plate 24, so as to exert a constant effort to yieldingly hold the outer face of the extractor-switch I9 against the inner face of the said side-plate 24. This displacement is especially clear in the showing of Fig. 8. The relatively-long tension-arm 3I of the spring 29 is hooked beneath a downwardly-facing spring-seat 32 constituting the under-face of a reinforcing-bar 33 rigidly secured to the outer face of the side-plate 24 in a location forwardly of the extractor-switch I9. When the tension-arm 3| is thus located in engagement with the spring-seat 32, the extractor-switch spring 29 acts through its key-portion 28 to yieldingly turn the extractor-switch I9 in such direction that the rear end of the said extractorswitch is raised and the forward end thereof is lowered. The turning movement just referred to is limited by the engagement of the upper face of the limiting-lug 25 of the extractor-switch I9 with the upper wall of the recess 26 in the sideplate 24, as is especially well shown in Figs. 3 m4.

Slightly forwardly of the extractor-switch I9 is located an upwardly and-forwardly-inclined cam-bar 34 rigidly secured to the inner face of the side-plate 24 and which in a manner as will hereinafter appear, is engaged by the guide-lug I8 of the cartridge-extractor I5.

When the machine gun is discharged, the barrel II and the barrel-extension I2 move rear- -wardly, under the recoil-forces, a relatively-short distance substantially from the positions in which they are shown in Fig. 2 into substantially the positions in which they are indicated in Fig. 1. The breech-bolt I3 will coincidentally trave1 rearwardly with the barrel II and barrel-extension I2 but its stroke will be greatly in excess of the stroke of the said parts II and I2. The breechbolt I3 will travel rearwarly into a position slightly to the rear of the position in which it is indicated in Fig. 1.

During the rearward travel of the breech-bolt, the cartridge-extractor I5 will, of course, travel therewith and will through the intermediary of its cartridge-extracting hook I6, withdraw a cartridge from the cartridge-belt I1 and carry such cartridge rearwardly. As the cartridge-extractor is moved rearwardly as described, the upper face of its forward portion will be in engagement with the extractor-depressing cam 2I on the underside of the top-plate 20, with the result that the forward portion of the said cartridge-extractor together with the cartridge carried by it, will be depressed. During this rearward travel and slightly beforet he guide-lug I8 clears the rear end of the extractor-switch I9, the said guide-lug I8 will engage with the upper surface of the said extractor-switch I9 and depress the rear end of the latter against the tension of the extractorswitch spring 29. This condition substantially corresponds to that shown in Fig. 1.

As the breech-bolt I3 moves further rearwardly from the position in which it is shown in Fig. 1, it will carry with it the cartridge-extractor I5, and slightly before the said breech-bolt reaches the limit of its rearward travel, the forward edge of the guide-lug I8 will ride rearwarly clear of the rear end of the extractor-switch I9. As soon as this clearance occurs, the extractor-switch spring 29 will assert itself and swing the rear end of the extractor-switch I9 upwardly. Now, during the subsequent forward travel of the breech-bolt I3 and its cartridge-extractor 15, the downwardly-and-forwardly-sloping cam-surface 35 of the extractor-switch I9 will be engaged by the forward upper portion of the guide-lug I8 of the cartridge-extractor I5. The engagement just referred to will further depress the forward end of the cartridge-extractor I5 and hence also the cartridge now carried thereby until the said cartridge is horizontally in line with the cartridgechamber of the barrel II. The said guide-lug will new travel forwardly in a path beneath the extractor-switch I9.

Ultimately during its forward travel coincidentally with the breech-bolt I3, the guide-lug I8 of the cartridge extractor I5 will engage with the upwardly-and-forwardly-sloping cam-bar 34, but only after the cartridge which is in process of being loaded into the cartridge-chamber of the barrel II has been partly inserted thereinto. The resultant lifting-action of the forward end of the cartridge-extractor I5 will lift the cartridge-extracting hook I6 thereof clear of the cannelure of the cartridge now partly inserted into the cartridge-chamber of the barrel I I.

In riding-up the surface of the cam-bar 34, the

guide-lug I8 of the extractor-switch [9 will upwardly crowd the forward end of the extractorswitch l9 against the tension of the extractorswitch spring 29, as indicated in Fig. 2.

In Fig. 2 the barrel H and barrel-extension l2 are shown in their full forward positionsand the breech-bolt i3 is shown in a position closely approaching its full forward or breech-closing position. As the cartridge-extractor l5 moves for.- wardly with the breech-bolt l3, from the position in which it is shown in Fig. 2 into its full breechclosing position, the rear end of the guide-lug l8 will clear the forward end of the extractor-switch l9, whereupon the forward end of the said extractor-switch will swing downwardly under the tension provided by the extractor-switch spring 29. In this manner the extractor-switch 19 will reassume its normal position, wherein the guidelug I8 of the cartridge-extractor I5 will ride over the top of the said extractor-switch when the breech-bolt is next moved rearwardly by the subsequent discharge of the machine sun.

In former practice and as is shown in the Browning patent above referred to, it was the custom to insert a U-shaped extractor-switch spring in the recess 25 of the side-plate 24 in such manner that one arm of such spring exerted an upward tension against th underside of the limiting-lug 25. Furthermore, in the prior construction the pivot-stud such as 22 of the extractor-switch was threaded at its outer end and the entire extractor-switch was retained in place by a nut bearing against the outer face of the side-plate 2 3 and retained by a suitable cotterpin. The described construction not only failed to provide a fully reliable extractor-switch spring in the cramped space available but also required that the aforesaid nut be adjusted with exactitude in order to prevent a binding action.

As will be seen from the foregoing and by reference to the accompanying drawings, the present invention provides an extractor-switch spring which not only serves the function of turning the extractor-switch but also acts as a positive key to hold the same in place in the side-plate 24. Furthermore, by suitably pre-tensioning the extractor-switch spring 29 (see Fig. 8), the said spring may be caused to yieldingly maintain the outer face of the extractor-switch firmly against the inner face of the side-plate 24.

By means of the present invention not only is the cost of the assembly reduced with respect to manufacturing operations and materials, but the assembly of the extractor-switch I9 with the sideplate 24 may be effected very rapidly and without requiring any delicate adjustments of the parts. Conversely, the disassembly of the parts for inspection or repair is similarly rendered most convenient.

The invention may be carried out in other specific ways than those herein set forth without departing from the spirit and essential characteristics of the invention, and the present embodiments are, therefore, to be considered in all respects as illustrative and not restrictive, and all changes coming within the meaning and equivalency range of the appended claims are intended to be embraced therein.

I claim: s 1. The combination with a machine gun having a breech-bolt and a pivotal cartridge-extrac-' tor carried by the said breech-bolt: of a hollow receiver-structure having a bearing-opening extending through a wall-portion thereof; a pivotal extractor-switch located mainly within the receiver-structure and constructed and arranged to deflect the cartridge-extractor of the machine gun, the said extractor-switch having a rigid trunnion extending outwardly through and beyond the bearing-opening in the adjacent walla bendable spring having one end held by the said receiver-structure and having its opposite end extended into the spring-receiving socket in the trunnion of the said extractor-switch to turn the said trunnion and hence also turn the said extractor-switch and to also act as a positive key 4 to limit the inward displacement of the said trunnion, the end of the spring which is entered into the socket in the trunnion of the extractorswitch being pre-set outwardly away from the outer face of the adjacent wall-portion of the receiver-structure to thereby draw the said trunnion outwardly.

2. The combination with a machine gun' having a breech-bolt and a pivotal cartridgeextractor carried by the said breech-bolt: of a hollow receiver-structure having a bearing-opening ex tending through a wall-portion thereof; a pivotal extractor-switch located mainly within the receiver-structure and constructed and arranged to deflect the cartridge-extractor of the machine gun, the said extractor-switch having a rigid trunnion extending outwardly through and beyond the bearing-opening in the adjacent wallportion of the said receiver-structure, the said trunnion having a spring-receiving socket therein located in its portion projecting outwardly be-' yond the said wall-portion; and a torsion-type spring having an inner end extended into the spring-receiving socket in the trunnion of the said extractor-switch to turn the said trunnion and hence also turn the said extractor-switch, the said spring having a loop-portion extending from its said inner end and also having an outer end extending from the said loop-portion away from the said inner end and engaged with a portion of the said receiver-structure; the inner end of the said torsion-type spring being pretensioned outwardly to exert a constant but-yielding ef fort to draw the said trunnion outwardly with respect to the said receiver-structure.

CARL G. SWEBILIUS. 

